IGCSE Biology Practice Test 14 – 60 Questions with Answers (Cambridge 0610)
Use this test to check your recall under timed conditions, then go back over any topic where you guessed an answer.
Characteristics and classification of living organisms
Q1. Which kingdom includes organisms that are multicellular, have no chloroplasts, and feed by absorbing nutrients from dead material?
- (A) Plant
- (B) Animal
- (C) Prokaryote
- (D) Fungus
Show Answer
Answer: D – Fungi are saprotrophic, secreting enzymes onto dead material and absorbing the digested products.
Q2. A student observes an animal with feathers, a beak, and wings. Which class is it in?
- (A) Mammal
- (B) Bird
- (C) Reptile
- (D) Amphibian
Show Answer
Answer: B – Feathers are unique to birds, which also lay hard-shelled eggs and have beaks.
Q3. Which life process is shown when a seedling grows taller over several weeks?
- (A) Excretion
- (B) Growth
- (C) Sensitivity
- (D) Respiration
Show Answer
Answer: B – Growth is a permanent increase in size or dry mass, as cells divide and enlarge.
Organisation of the organism
Q4. Which level of organisation is the heart an example of?
- (A) An organ
- (B) A tissue
- (C) A cell
- (D) An organ system
Show Answer
Answer: A – The heart is an organ made of several tissues working together to pump blood.
Q5. Which structure is found in both plant and animal cells?
- (A) Chloroplast
- (B) Cell wall
- (C) Mitochondrion
- (D) Large permanent vacuole
Show Answer
Answer: C – Mitochondria carry out aerobic respiration in both plant and animal cells.
Q6. A red blood cell has no nucleus and a biconcave shape. How does this help its function?
- (A) It allows the cell to divide rapidly
- (B) It allows the cell to photosynthesise
- (C) It allows the cell to fight pathogens
- (D) It gives more space for haemoglobin and a large surface area for gas exchange
Show Answer
Answer: D – Without a nucleus there is more room for haemoglobin, and the biconcave shape increases surface area for oxygen diffusion.
Movement into and out of cells
Q7. Which statement about osmosis is correct?
- (A) It is the diffusion of any particle through a membrane
- (B) It needs energy from respiration
- (C) It moves solutes from low to high concentration
- (D) It is the diffusion of water through a partially permeable membrane
Show Answer
Answer: D – Osmosis specifically describes water moving from a dilute to a more concentrated solution across a partially permeable membrane.
Q8. A cell membrane is described as partially permeable. What does this mean?
- (A) Nothing can pass through it
- (B) Some substances can pass through it but others cannot
- (C) All substances pass through it equally and freely at all times
- (D) Only water can pass through it
Show Answer
Answer: B – A partially permeable membrane lets small molecules such as water pass, while blocking larger or charged particles.
Q9. Which change would slow down diffusion of a gas into a cell?
- (A) Increasing the concentration gradient
- (B) Decreasing the temperature
- (C) Increasing the surface area
- (D) Decreasing the diffusion distance
Show Answer
Answer: B – Lower temperature means particles move more slowly, so diffusion happens at a lower rate.
Biological molecules
Q10. Which molecule is a polysaccharide made only of glucose units?
- (A) Protein
- (B) Fat
- (C) Starch
- (D) DNA
Show Answer
Answer: C – Starch is a large carbohydrate built from many glucose molecules joined together.
Q11. Vitamin C is tested using DCPIP solution. What colour change shows vitamin C is present?
- (A) Blue DCPIP becomes colourless
- (B) Blue DCPIP becomes brick-red
- (C) Brown iodine becomes blue-black
- (D) Blue biuret becomes purple
Show Answer
Answer: A – Vitamin C is a reducing agent that decolourises blue DCPIP, and the volume needed shows its concentration.
Q12. Which statement about fats is correct?
- (A) Fats contain nitrogen
- (B) Fats are made of amino acids
- (C) Fats are a concentrated energy store, insoluble in water
- (D) Fats dissolve easily in water
Show Answer
Answer: C – Fats store more energy per gram than carbohydrates and do not dissolve in water, making them good storage molecules.
Enzymes
Q13. At low temperature, an enzyme reaction is slow. What is the main reason?
- (A) The enzyme is denatured
- (B) The substrate is destroyed
- (C) The pH becomes zero
- (D) Molecules move slowly and collide with active sites less often
Show Answer
Answer: D – Low temperature reduces kinetic energy, so enzyme-substrate collisions are rarer, but the enzyme is not denatured.
Q14. Which graph shape describes the effect of pH on enzyme activity?
- (A) A curve rising to a peak at the optimum pH, then falling
- (B) A straight line rising continuously
- (C) A flat line with no change
- (D) A curve falling continuously from pH 1
Show Answer
Answer: A – Activity is highest at the optimum pH and falls on either side as the enzyme shape is increasingly disrupted.
Q15. Trypsin is an enzyme that works in the small intestine. What is its optimum pH most likely to be?
- (A) pH 2, strongly acidic like stomach acid
- (B) Around pH 8, slightly alkaline
- (C) pH 14, strongly alkaline
- (D) pH 0, extremely acidic
Show Answer
Answer: B – Pancreatic enzymes such as trypsin work best in the slightly alkaline conditions of the small intestine.
Plant nutrition
Q16. A plant is grown with plenty of light and water but no carbon dioxide. What happens to photosynthesis?
- (A) It cannot occur, because carbon dioxide is a raw material
- (B) It continues using oxygen instead
- (C) It continues at the same rate
- (D) It produces starch from water alone
Show Answer
Answer: A – Without carbon dioxide there is no carbon source for making glucose, so photosynthesis stops.
Q17. Which leaf adaptation reduces water loss while still allowing gas exchange?
- (A) A very thick cuticle with no stomata at all on the leaf
- (B) A large number of chloroplasts
- (C) Stomata that can close when water is scarce
- (D) A thin leaf with a huge surface
Show Answer
Answer: C – Closing stomata cuts water loss, though it also slows gas exchange, which is a trade-off the plant manages.
Q18. Magnesium deficiency in a plant first shows in older leaves. What symptom appears?
- (A) Purple stems
- (B) Wilting in bright light only
- (C) Stunted roots with no other sign
- (D) Yellowing between the veins
Show Answer
Answer: D – Without magnesium the plant cannot make chlorophyll, so leaves turn yellow, a condition called chlorosis.
Human nutrition
Q19. Which enzyme is produced in the stomach and begins the digestion of protein?
- (A) Amylase
- (B) Lipase
- (C) Maltase
- (D) Pepsin
Show Answer
Answer: D – Pepsin is secreted in the stomach and breaks down proteins in acidic conditions.
Q20. Peristalsis moves food along the gut. How does it work?
- (A) Cilia sweep food along the wall
- (B) Rings of muscle contract behind the food and relax in front of it
- (C) Gravity pulls food downwards only
- (D) Digestive juices push food along
Show Answer
Answer: B – Waves of muscle contraction behind the bolus push it along the alimentary canal.
Q21. Iron is an important mineral in the diet because it is needed to make which substance?
- (A) Haemoglobin
- (B) Insulin, a hormone controlling blood glucose
- (C) Bile
- (D) Cellulose
Show Answer
Answer: A – Iron is a component of haemoglobin, so iron deficiency leads to anaemia and reduced oxygen transport.
Transport in plants
Q22. Which statement about translocation in phloem is correct?
- (A) It carries water upwards only
- (B) It needs no energy
- (C) It moves sugars and amino acids from sources to sinks
- (D) It takes place in dead xylem vessels throughout the stem
Show Answer
Answer: C – Phloem transport is an active process moving dissolved food to growing or storage regions.
Q23. A leafy shoot is placed in water with the stem cut underwater. Why is the stem cut underwater?
- (A) To prevent air entering the xylem and blocking water uptake
- (B) To kill bacteria on the stem
- (C) To make the shoot heavier
- (D) To stop photosynthesis in the stem
Show Answer
Answer: A – Air bubbles in xylem break the continuous water column, so cutting underwater keeps the column intact.
Q24. Which factor would increase the rate of water uptake by a plant?
- (A) Closing all stomata
- (B) Lowering the temperature sharply
- (C) Increasing light intensity
- (D) Raising the humidity to saturation
Show Answer
Answer: C – More light opens stomata and increases photosynthesis, raising transpiration and therefore water uptake.
Transport in animals
Q25. What is the double circulation in mammals?
- (A) Blood passes through the heart once per circuit
- (B) Blood flows in both directions in the same vessel
- (C) The heart beats twice for each breath
- (D) Blood passes through the heart twice in one complete circuit of the body
Show Answer
Answer: D – Blood goes heart to lungs to heart to body, so it passes through the heart twice per circuit, keeping oxygenated and deoxygenated blood separate.
Q26. Which blood vessel has the thinnest wall, only one cell thick?
- (A) Artery, a thick-walled high-pressure vessel
- (B) Capillary
- (C) Vein
- (D) Aorta
Show Answer
Answer: B – Capillary walls are one cell thick, giving a short diffusion distance for exchange with tissues.
Q27. What happens to blood as it passes through the lungs?
- (A) It loses oxygen and gains carbon dioxide
- (B) It gains oxygen and loses carbon dioxide
- (C) It gains urea and loses glucose
- (D) It loses plasma and gains platelets
Show Answer
Answer: B – In the lung capillaries, oxygen diffuses into the blood and carbon dioxide diffuses out into the alveoli.
Diseases and immunity
Q28. Which pathogen causes tuberculosis?
- (A) A bacterium
- (B) A virus
- (C) A fungus
- (D) A protoctist
Show Answer
Answer: A – Tuberculosis is a bacterial disease spread in droplets when an infected person coughs.
Q29. How do antibodies help to defend the body?
- (A) They engulf bacteria directly
- (B) They produce memory cells
- (C) They bind to antigens on pathogens, marking them for destruction
- (D) They block blood vessels to trap pathogens
Show Answer
Answer: C – Each antibody fits a specific antigen, and binding helps phagocytes recognise and destroy the pathogen.
Q30. Which control measure is most effective against the spread of malaria?
- (A) Vaccinating against bacteria
- (B) Boiling all drinking water
- (C) Washing hands before meals
- (D) Using insecticide-treated bed nets and draining standing water
Show Answer
Answer: D – Malaria is spread by mosquitoes, so reducing bites and mosquito breeding sites cuts transmission.
Gas exchange in humans
Q31. Which gas is present in the highest percentage in inhaled air?
- (A) Oxygen
- (B) Carbon dioxide
- (C) Water vapour
- (D) Nitrogen
Show Answer
Answer: D – Air is about 78 percent nitrogen, which is not used in gas exchange and stays at a similar level in exhaled air.
Q32. A person breathes out into limewater and it turns milky. What does this show?
- (A) Exhaled air contains more oxygen
- (B) Exhaled air contains carbon dioxide
- (C) Exhaled air contains nitrogen
- (D) Exhaled air contains no water vapour
Show Answer
Answer: B – Carbon dioxide reacts with limewater to form a milky precipitate of calcium carbonate.
Q33. Why is exhaled air warmer and more humid than inhaled air?
- (A) It has passed over moist, warm surfaces in the airways and lungs
- (B) It has been heated by the stomach
- (C) It contains extra nitrogen from the blood
- (D) It has lost all its oxygen
Show Answer
Answer: A – Air is warmed and moistened as it travels through the nose, trachea and lungs before being breathed out.
Respiration
Q34. Which process releases energy for cell division in a growing root tip?
- (A) Photosynthesis
- (B) Transpiration
- (C) Respiration
- (D) Diffusion
Show Answer
Answer: C – All energy-requiring cell activities, including division and protein synthesis, are powered by respiration.
Q35. Anaerobic respiration in human muscle produces less energy per glucose molecule than aerobic respiration because of which fact?
- (A) Glucose is only partly broken down to lactic acid
- (B) No glucose is used at all
- (C) Oxygen is stored in the muscle
- (D) Lactic acid contains no energy
Show Answer
Answer: A – Partial breakdown leaves much energy still locked in lactic acid, so less is released than in complete aerobic breakdown.
Q36. Yeast is used in baking because anaerobic respiration produces which gas?
- (A) Oxygen
- (B) Nitrogen, the most common gas in the air
- (C) Carbon dioxide
- (D) Hydrogen
Show Answer
Answer: C – Carbon dioxide bubbles expand the dough, making bread rise, while ethanol evaporates during baking.
Excretion in humans
Q37. Which substances are normally found in the filtrate in Bowman’s capsule but not in urine?
- (A) Urea and excess salts, which appear in urine
- (B) Water and urea
- (C) Salts and water
- (D) Glucose and amino acids
Show Answer
Answer: D – Glucose and amino acids are filtered out of the blood but are fully reabsorbed in the tubule in a healthy kidney.
Q38. The hormone ADH is released when blood water content falls. What is its effect on the kidney?
- (A) It reduces filtration in the glomerulus
- (B) It increases water reabsorption from the collecting duct
- (C) It increases urea production in the liver
- (D) It stops urine formation completely
Show Answer
Answer: B – ADH makes the collecting duct more permeable to water, so more water returns to the blood and urine is concentrated.
Q39. Which organ removes excess amino acids and converts them for excretion?
- (A) Kidney
- (B) Liver
- (C) Spleen
- (D) Bladder
Show Answer
Answer: B – The liver deaminates excess amino acids, forming urea for the kidneys to excrete.
Coordination and response
Q40. Which part of the nervous system coordinates a reflex action without involving conscious thought?
- (A) The spinal cord
- (B) The cerebrum
- (C) The cerebellum only
- (D) The sensory receptor
Show Answer
Answer: A – In a spinal reflex, impulses pass through the spinal cord and back out, giving a fast response without the brain deciding.
Q41. In dim light, the pupil dilates. Which muscles bring this about?
- (A) Ciliary muscles
- (B) Circular muscles of the iris contract
- (C) Radial muscles of the iris contract
- (D) Muscles of the lens contract
Show Answer
Answer: C – Radial muscles pull the iris outward, widening the pupil so more light can enter in dim conditions.
Q42. A shoot bends towards light. Which hormone causes this response?
- (A) Insulin
- (B) Adrenaline
- (C) Thyroxine
- (D) Auxin
Show Answer
Answer: D – Auxin moves to the shaded side of the shoot, where it speeds cell elongation and bends the shoot towards light.
Drugs
Q43. Which statement about drug misuse is correct?
- (A) All drugs are harmful in any dose
- (B) Misuse means using any medicine at all
- (C) Prescribed drugs can never be misused
- (D) Misuse includes taking a drug in a way or amount that harms health
Show Answer
Answer: D – Misuse covers taking too much, taking another person’s medicine, or using a drug for a non-medical purpose.
Q44. Heroin slows down the nervous system. Which group of drugs does it belong to?
- (A) Stimulants
- (B) Depressants
- (C) Antibiotics
- (D) Painkillers only
Show Answer
Answer: B – Depressants slow brain and body activity, while stimulants speed it up.
Q45. Smoking during pregnancy increases the risk of which outcome?
- (A) Low birth weight of the baby
- (B) Extra fingers on the baby
- (C) The baby being born with teeth
- (D) The mother producing no milk at all
Show Answer
Answer: A – Carbon monoxide and nicotine reduce oxygen supply to the baby, often leading to lower birth weight.
Reproduction
Q46. In a flowering plant, fertilisation occurs when a pollen nucleus fuses with which cell?
- (A) A sepal cell
- (B) A stigma cell, where pollen first lands
- (C) The egg cell in the ovule
- (D) A petal cell
Show Answer
Answer: C – One male nucleus from the pollen tube fuses with the egg cell, forming the zygote.
Q47. Which structure in the human female produces eggs?
- (A) The ovary
- (B) The uterus
- (C) The cervix
- (D) The oviduct
Show Answer
Answer: A – Eggs are produced in the ovaries and released at ovulation into the nearby oviduct.
Q48. A gardener takes cuttings from a plant to grow new plants. What is the genetic relationship between the cuttings and the parent?
- (A) They are genetically unrelated to the parent plant
- (B) They share half their genes with the parent
- (C) They are genetically identical to the parent
- (D) They have twice as many chromosomes
Show Answer
Answer: C – Cuttings are a form of asexual reproduction, so the new plants are clones of the parent.
Inheritance
Q49. What is the phenotype of an organism?
- (A) The genes it carries
- (B) The chromosomes in its cells
- (C) The alleles on one chromosome
- (D) The observable characteristics resulting from its genes and environment
Show Answer
Answer: D – Phenotype is what can be seen or measured, produced by genotype interacting with the environment.
Q50. A heterozygous tall plant (Tt) is crossed with a short plant (tt). What proportion of offspring is expected to be short?
- (A) None
- (B) One half
- (C) Three quarters
- (D) All
Show Answer
Answer: B – The cross gives Tt and tt in equal numbers, so half the offspring are short.
Q51. Which type of reproduction produces offspring with new combinations of alleles?
- (A) Binary fission
- (B) Sexual reproduction
- (C) Budding
- (D) Vegetative propagation
Show Answer
Answer: B – Meiosis and fertilisation combine alleles from two parents, creating varied offspring.
Variation and selection
Q52. A mutation in a gene can lead to which outcome?
- (A) A change in the protein made from that gene
- (B) An exact copy of the original gene with no change
- (C) No change in any cell
- (D) A doubling of all chromosomes
Show Answer
Answer: A – Changing the DNA sequence can change the amino acid sequence, altering or disabling the protein.
Q53. In an environment that becomes colder, which individuals are most likely to survive by natural selection?
- (A) Those with the thinnest fur, losing heat quickly
- (B) Those that reproduce slowest
- (C) Those best adapted to cold conditions
- (D) Those that arrived most recently
Show Answer
Answer: C – Natural selection favours individuals whose traits suit the current environment, and they pass those traits on.
Q54. Which example shows variation caused by both genes and environment?
- (A) Blood group
- (B) Tongue rolling ability
- (C) Number of fingers
- (D) Body mass
Show Answer
Answer: D – Body mass is influenced by inherited factors and by diet and activity, so it shows both kinds of variation.
Organisms and their environment
Q55. Which process returns carbon dioxide to the atmosphere from dead organisms?
- (A) Photosynthesis
- (B) Feeding by herbivores, which eat producers
- (C) Growth of producers
- (D) Respiration by decomposers
Show Answer
Answer: D – Decomposers respire as they break down dead material, releasing carbon dioxide for photosynthesis.
Q56. In a food web, removing the top predator is most likely to cause which change?
- (A) Producers to disappear at once
- (B) Herbivore numbers to rise, then producer numbers to fall
- (C) All other species to increase equally
- (D) Decomposers to stop working
Show Answer
Answer: B – Without predation, herbivores multiply and overgraze producers, which can then decline sharply.
Human influences on ecosystems
Q57. Which practice helps to conserve fish stocks in the oceans?
- (A) Setting catch quotas and protected areas
- (B) Fishing during breeding seasons only, when stocks are low
- (C) Using finer nets to catch young fish
- (D) Increasing the size of fishing fleets
Show Answer
Answer: A – Quotas limit the total catch and protected areas let fish breed, helping stocks recover.
Q58. Burning forests to clear land for cattle adds to global warming in two ways. Which pair is correct?
- (A) It removes oxygen and adds nitrogen
- (B) It adds water vapour and removes soil
- (C) It releases carbon dioxide and removes trees that would absorb it
- (D) It releases methane and removes rainfall
Show Answer
Answer: C – Burning releases stored carbon, and losing trees reduces future carbon dioxide uptake by photosynthesis.
Biotechnology and genetic modification
Q59. Penicillin is produced by which organism in a fermenter?
- (A) A fungus
- (B) A bacterium
- (C) A virus
- (D) A green alga
Show Answer
Answer: A – Penicillin is an antibiotic made by the fungus Penicillium, grown under controlled conditions in a fermenter.
Q60. Which statement is a possible risk of using genetically modified organisms?
- (A) They always cost more to grow
- (B) They never survive outside a laboratory
- (C) A modified trait could affect non-target species in the ecosystem
- (D) They contain no genes at all
Show Answer
Answer: C – For example, a pest-resistant crop could harm insects that were not the target, so effects must be assessed before release.
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